Metal immunity in a reverse magnetic system

摘要

A method for tracking an object includes fixing to the object a transmitter for transmitting a position-indicative magnetic field and providing a map of distortion of the position-indicative magnetic field caused by the object. A distorted magnetic field transmitted from the object is sensed. The distorted magnetic field includes the position-indicative magnetic field subject to the distortion caused by the object. Estimated coordinates of the object based on the sensed, distorted magnetic field are determined. The estimated coordinates and the map are used to compute corrected coordinates.